on board computer

[alstbernard]

I bought an obd Innova model no 3140 and i tried it on my car a nissan wingroad 2001.When i hooked it to the car the unit said cannot establish a link between the car and the unit, I then tried the unit on a Hyundai and the unit linked the vehicle's computer and the obd and gave a code 421. On my car the Nissan it gave no information it only saidprotocol iso9141.Thank you.